Such an apparatus gathers the foil longitudinally in accordion-like folds and then stretches it outward. When in this stretched condition, the gathering device with the accordions folded foil or the pull-down device, when the gathered foil has previously been transferred to one, is moved downward along the stack so that the gathered foil is expanded down over the stack. The gathered foil is here stretched after being transferred to the pull-down device.
In a known device in order to gather the foil there are, on opposite connecting lines between two adjacent gathering fingers, roller assemblies each formed by a gathering wheel and a counter roller. The gathering wheel is outside and the counter roller inside the foil so that the foil is pinched between the gathering wheel and the counter roller. The rotation axis of the counter roller is above the axis of the respective gathering wheel, that is toward the gathered end of the foil that is normally gathered vertically.
A disadvantage of this known apparatus is that the folds of the gathered end of the foil section do not always extend in the same orientation and all of the folds formed by gathering do not extend downward and outward, but instead are partly inward and downward. When a thus gathered foil is stretched and pulled down over the stack, it is not possible to pull down the foil uniformly, since the downwardly and outwardly directed folds hinder the movement of the downwardly and inwardly extending folds as result of the tension.